The present invention relates to an apparatus and process for adhesive bonding. More particularly, the present invention relates to an apparatus and process for applying adhesive to bond a strand component to an appointed substrate or article.
Adhesives have been widely employed to assemble components to form various types of manufactured articles. In particular, adhesives have been employed to attach components, such as elastomeric members, in disposable articles. Such disposable articles have included absorbent articles, such as disposable diapers, feminine care products, children""s training pants, adult incontinence products and the like.
Spray applicators have employed selected air streams to deposit adhesive onto selected components, such as elastic strands. In addition, known techniques have been employed to helically wrap a filament of adhesive around an elastic strand. Other spray applicators have been employed to assemble the various components of a desired product, such as a disposable diaper. The spray applicators have, for example, been configured to form spiraling spray patterns, swirling spray patterns, and other back-and-forth spray patterns.
In various products, elastic strands have been laminated between layers of polymer film and/or layers of woven or nonwoven fabrics to provide elasticized regions. Folded-over layers have also been employed to enclose or envelop selected strands of material. For example, the folded-over layers have been employed to enclose elastomeric strands within the waistband, leg cuff and inner barrier cuff components of disposable diapers and other disposable absorbent articles.
Conventional adhesive bonding techniques and conventional forming techniques, such as those described above, have shown a need for further improvement. Conventional spray applicators, for example, have exhibited an excessive blow-by of the adhesive, and have not adequately provided a desired combination of secure bonding, creep resistance and low interference with the stretching and retracting properties of adhered elastomeric strands. Conventional forming techniques have not exhibited desired levels of efficiency and effectiveness when producing desired components and component laminates. For example, the conventional techniques have not reliably provided the desired coating of elastic strands with adhesive. Additionally, the techniques have been excessively susceptible to various disruptive factors, such as the blockage of adhesive passages and outlet ports, the blockage of air passages and outlet ports, the weaving of the elastic strands, and variations in the pressures applied to the adhesive material and the process air streams. As a result, the conventional techniques have not adequately provided components having desired combinations of flexibility and leakage resistance, and there remains a need for improved methods for forming desired assemblies and for adhering components, such as elastomeric components, into an assembled article.
Generally stated, the present invention provides a distinctive method and apparatus for forming an article which includes one or more distinctively configured strands of material. In particular aspects, the invention can provide a method and apparatus for wrapping a strand of material with a selected filament, and desirably, the filament may be an adhesive filament. The technique of the invention can include a moving of a strand of material at a selected speed along an appointed machine-direction. At least a first, substantially continuous, filament can be directed onto the strand of material along an oscillating filament path to form a first plurality of filament threads extending from opposed lateral side regions of the strand of material. Additionally, an air stream can be directed to operatively wrap the filament threads around the strand of material. A particular aspect of the invention can further include a directing of at least a substantially continuous, second filament onto the strand of material along a corresponding oscillating filament path. The second filament can form a second plurality of filament threads disposed at opposed lateral side regions of said strand of material.
Another aspect of the present invention can provide a method for incorporating at least one, and desirably a plurality, of strands of material into a manufactured article. In particular aspects, at least one first strand of material is moved along an appointed machine-direction. The at least one first strand of material is attached to a substrate, such as a base layer of material, to provide a substrate composite, and a laminate layer can be placed adjacent the at least one first strand of material. At least one second strand of material can be moved along its appointed machine-direction, and the at least one second strand of material can be attached to the base layer. A portion of the base layer can be folded to substantially enclose the at least one first strand and the laminate layer. Alternatively or additionally, a portion of the base layer can be folded to substantially enclose the at least one second strand with the base layer material.
In another aspect of the invention, the at least one first strand of material can be moved along its appointed machine-direction, and attached to the base layer of material to provide the substrate composite. The laminate layer can be placed onto the at least one first strand of material, and at least one third strand of material can be moved along its appointed machine-direction, and can be attached to the laminate layer. An appointed portion of the base layer can be folded to substantially enclose the at least one first strand, the laminate layer and the at least one third strand with the base layer material.
In its various aspects, the present invention can more effectively and efficiently produce an article which includes one or more target strands of material. For example, the technique of the invention can more reliably provide the desired coating of elastic strands with adhesive. Additionally, the present invention can be less susceptible to various disruptive factors, such as the blockage of adhesive passages and adhesive outlet ports, the blockage of air passages and air outlet ports, the weaving of the target strands, and the variations that can occur in the pressures applied to the adhesive material and the air streams during the operation of the process. The process and apparatus of the invention can better accommodate any weaving of the strands, and reduce the likelihood of having the adhesive completely miss its target strand. As a result the technique of the invention can more reliably apply a desired, operative amount of adhesive on each target strand.
Where the technique of the invention is configured to wrap a material strand with one or more adhesive filaments, for example, the technique can exhibit less blow-by of the adhesive, help reduce cost and can provide a desired combination of secure bonding and creep resistance. Where the technique is configured to wrap an elastomeric strand with adhesive, the technique can provide a low interference with the stretching and retracting properties of the elastomeric strands. Where the technique of the invention is configured to include the dividing of at least one elastomeric strand of material into a plurality of strand segments to provide a substantially nongathering section of the at least one strand the laminate composite can provide a more effective component which can be advantageously configured to generate improved gasketing and improved fit. Products which incorporate the components that are produced in accordance with the present invention can advantageously exhibit improved combinations of fit, flexibility, comfort and leakage resistance.